Radio-frequency generator for powering an ablation device

Abstract

An apparatus and method for use in performing ablation of organs and other tissues includes a radio frequency generator which provides a radio frequency signal to ablation electrodes. The power level of the radio frequency signal is determined based on the subject area of ablation. The radio frequency signal is coupled with the ablation electrodes through a transformation circuit. The transformation circuit includes a high impedance transformation circuit and a low impedance transformation circuit. The high or low impedance transformation circuit is selected based on the impedance of the ablation electrodes in contact with the subject tissue. Vacuum level, impedance level, resistance level, and time are measured during ablation. If these parameters exceed determinable limits the ablation procedure is terminated.

1. A method of ablating tissue, comprising:
 positioning an RF ablation device into contact with target tissue to be ablated, wherein the RF ablation device includes an applicator head comprising a plurality of flextures, whereby the RF ablation device determines at least one dimension of a target area of the tissue by transducing physical distance separation of at least two of the flextures of the RF ablation device; 
 receiving the at least one dimension to an RF generator system operable to output any of a plurality of RF power levels, the RF generator operable to select an appropriate RF power level output to the RF ablation device based on the at least one dimension; wherein the RF generator automatically selects between a low-impedance transformation circuit and a high-impedance transformation circuit; and 
 receiving an RF signal at the selected RF power to the RF ablation device for use in ablating the target area of the tissue. 
 
     
     
       2. The method of  claim 1 , further comprising: applying vacuum pressure to the RF ablation device. 
     
     
       3. The method of  claim 2 , further comprising:
 measuring the vacuum pressure applied to the RF ablation device; and 
 generating a fault if the vacuum pressure falls outside a predetermined range. 
 
     
     
       4. The method of  claim 1 , further comprising:
 measuring a duration of ablation; and 
 terminating ablation if the measured duration exceeds a predetermined limit. 
 
     
     
       5. The method of  claim 1 , wherein the positioning step includes positioning the ablation device into contact with a uterus. 
     
     
       6. The method of  claim 1 , wherein the method further includes using a measuring device to obtain the dimensions of the target area to be ablated. 
     
     
       7. The method of  claim 1 , wherein the RF generator automatically selects an appropriate RF power level in proportion to at least one of the length and width of the target area to be ablated.